Document Type : Research Article
Background: Postoperative pain is one of the most common concern for people undergoing surgery. Preventing and treating postoperative pain is crucial to the patient's early mobilisation and well-being. Pre-emptive analgesia prevents central sensitization caused by incisional and inflammatory damage during surgery and the early postoperative period and has the potential to be more effective than a similar analgesic treatment started after surgery, reducing immediate postoperative pain and preventing the development of chronic pain by reducing altered central sensory processing.Pregabalin, a GABA analogue, is effective in the treatment of neuropathic pain, incisional injury and inflammatory injury. Perioperative administration of pregabalin is reported to reduce perioperative anxiety, opioid consumption and opioid related side effects. Amitriptyline inhibits the neuronal reuptake of serotonin and norepinephrine which is an important physiologically to terminate transmitting activity. The inhibition of norepinephrine reuptake increases the levels of norepinephrine in the posterior grey column of spinal cord. This increased levels of norepinephrine increases basal activity of alpha 2 adrenergic receptors which increases GABA transmission among spinal interneurons thereby mediating analgesic effect. Also, the sodium channel blocking effect of amitriptyline contributes to its analgesic activity.
Aims:To evaluate and compare the pre-emptive analgesic efficacy of oral pregabalin versus oral amitriptyline in patients undergoing elective inguinal hernioplasty surgeries under spinal anaesthesia and to assess the incidence of adverse effects of both drugs.
Materials and Methods: 90 patients of ASA 1 and 2 were randomized into three groups as Group A (Amitriptyline 10mg, n=30) and Group B (Pregabalin 75 mg,n=30) and Group C (Placebo,n=30). Patients received placebo or either of the study drugs 2 hours before surgery. Demographic data, postoperative pain score, sedation score, time since spinal anaesthesia to requirement of first rescue analgesic, total opioid consumption in 24 hours and side effects were recorded.
Results: Time for first rescue analgesic was longer in Group B as compared to Group A and Group C, although statistically insignificant. There was no significant reduction in mean VAS score and sedation score between the three groups. The three groups were comparable in terms of total postoperative opioid consumption. Side effects were negligible with both the drugs.
Conclusion: Single preemptive oral pregabalin 75 mg and oral amitriptyline 10 mg is ineffective in reducing the severity of postoperative pain as compared to placebo in patients undergoing inguinal hernioplasty.